Many different types of metal enclosures exist for holding a printed circuit board (PCB) and which provide a physical and/or electrical contact between the enclosure and the PCB for different purposes such as holding the PCB in position within the enclosure and for providing an electrical grounding connection between the enclosure and a given area of the PCB. For several reasons, including electromagnetic compatibility (EMC), it is frequently necessary to provide multiple different electrical grounding connections between a PCB and a metal enclosure holding the PCB.
Various methods of making enclosures of metal and providing an electrical connection between such enclosures and PCBs exist today. Each method has advantages and drawbacks. Enclosures formed of sheet metal are able to be formed inexpensively and are able to be provided with integral spring portions, such as, for example, by stamping and being portions of a flat wall. However, enclosures of sheet metal include several design limitations inherent in the process of bending and forming a thin metal sheet. Sheet metal enclosures are also generally less effective at dissipating heat than enclosures of cast metal, making them unsuitable for many applications requiring relatively high amounts of energy to be dissipated in the form of heat and without exceeding temperature thresholds. Enclosures of cast metal have historically had their own set of drawbacks including relatively wide tolerances and brittle materials. The wide tolerances in traditional cast metal enclosures required flexible connections to have a correspondingly large range of travel while maintaining the necessary contact pressure between the enclosure and the PCB. The brittle nature of traditional cast metal enclosures prevented the enclosures from being integrally formed with spring portions that were capable of operating over the large range of travel, which necessitated additional components to provide a flexible and electrically conductive connection between the enclosure and a PCB located therein. One such arrangement that includes additional components is shown in FIG. 1, which uses a compressible pad, such as a surface mount technology (SMT) pad from W. L. Gore & Associates, Inc. (Gore® pad) that is soldered to the PCB and which makes electrically conductive connection with a corresponding post that is formed in a wall of the enclosure. Springs of wire or stamped metal are also sometimes soldered to a PCB for this purpose. While functional, components such as Gore® pads or metal springs add cost and complexity to products that use them. Resilient materials such as those used in Gore® pads may also be susceptible to break-down and/or tearing, which may reduce their effectiveness over time. This cost and complexity is exacerbated in devices that require multiple grounding connections. Therefore, there exists a need for an inexpensive and reliable electrical connection between an enclosure of cast metal and a PCB located therein and which does not require additional components.